21221220211 has 8 divisors (see below), whose sum is σ = 21407016960. Its totient is φ = 21035896968.

The previous prime is 21221220203. The next prime is 21221220233. The reversal of 21221220211 is 11202212212.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21221220211 - 2³ = 21221220203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21221220271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28051 + ... + 207916.

It is an arithmetic number, because the mean of its divisors is an integer number (2675877120).

Almost surely, 2^21221220211 is an apocalyptic number.

21221220211 is a deficient number, since it is larger than the sum of its proper divisors (185796749).

21221220211 is a wasteful number, since it uses less digits than its factorization.

21221220211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236753.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21221220211 its reverse (11202212212), we get a palindrome (32423432423).

The spelling of 21221220211 in words is "twenty-one billion, two hundred twenty-one million, two hundred twenty thousand, two hundred eleven".